Astrobiology is the study of life throughout the universe and on earth. This interdisciplinary field encompasses the search for biologically habitable extra-solar planets, evidence of pre-biotic chemistry and laboratory/field research on life's potential to adapt to challenges in outer-space. Astrobiologists use physics, chemistry, astronomy, biology, molecular biology, ecology, planetary science, geography and geology in their research. One of the key areas of research activity for Astrobiologists is the exploration of Mars and its potential for harbouring extra-terrestrial life, both in the past and in the present.

1324. Which one of the following best replaces "encompasses" while maintaining the meaning of the sentence?

(a) Incorporates

(b) Combines

(c) Joins

(d) Syndicates

1325. Which one of the following best replaces "key" while maintaining the meaning of the sentence?